Omega-3 fatty acid supplements, like fish oil, have been studied for dyslipidemia. They have reliably been found to result in relatively large reductions in triglycerides, and inconsistently increase LDL-C and HDL-C to a minor degree.[1][2][3] They may increase bleeding risk, so those on anticoagulant drugs should be cautious of taking these supplements.[4]
Another supplement that has been studied for dyslipidemia is red yeast rice. Red yeast rice sometimes contains monacolin K, which is identical to the statin lovastatin. For this reason, red yeast rice products containing non-negligible amounts of monacolin K are banned by the FDA since they are a “non-approved drug”.[5][6] If monacolin K is present, red yeast rice may have similar effects and safety profiles to statins.[7][8] However, the methodology for assessing safety in trials is often poor.[8]
Additionally, garlic supplements decrease total cholesterol and LDL-C, though not consistently, with unclear impacts on HDL-C.[9][10] Effects on LDL-C and HDL-C may occur less often when garlic supplements are given alongside a lipid-lowering diet.[11][12][13].
Finally, psyllium fiber can have beneficial effects not only on LDL-C, but on non-HDL-C and apolipoprotein B levels, which may be more predictive of cardiovascular disease than LDL-C.[14]